Step Length in Forward Differencing for Curved Surface Display

摘要

Forward Differencing (FD) is a technique to evaluate polynomial functions atintervals of equal length, the step length. Adaptive Forward Differencing (AFD) is a variant of FD in which the step length can be adjusted during evaluation. Both are used in scanning/display algorithms for parametric polynomial surfaces by generating and displaying a set of points. An FD algorithm and an AFD algorithm for the evaluation of a polynomial with one parameter are presented. Constraints on the set of generated surface points to produce a satisfactory picture are formulated. Two known surface scanning/display algorithms are evaluated with these constraints and improvements are presented.